It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
Past El Niño events during the northern hemisphere autumn and winter have been associated, among others, with drier than normal conditions in parts of Australia, Indonesia, the Philippines, northeastern Brazil, southeastern Africa and parts of Asia.
Wetter than normal conditions have, in the past, tended to be experienced in Ecuador and northern Peru, as well as southern Brazil to central Argentina and parts of eastern Africa. El Niño winters tend to be mild over western Canada and parts of the northern United States, and wet over the southern United States.
The NAO or North Atlantic Oscillation is simply a "blocking" pattern that allows for cold air to slow down and allows LOW pressure to form off the coast and has time to explode into snowstorms.
It's basically the traffic cop of weather. Slow the pattern down and the odds of a juiced up system getting into the Eastern Part of the U.S. starts to increase. Negative NAO = More storm chances east of the Mississippi River.
The AO has a positive and negative phase, and is closely related to the NAO. It is not common for the NAO and AO to both be in the same phase at the same time. In the positive phase, the polar vortex that holds cold air up in the Arctic is strengthened, and the cold air is locked up north. However, in the negative phase, this vortex weakens, and the cold air is unleashed south into the US.
It’s no coincidence that the regional-scale air pressure patterns linked to the North Atlantic Oscillation are visible in the same maps used to illustrate the Arctic Oscillation. The similarity makes sense: many meteorologists consider the North Atlantic Oscillation to be a “regional subset” of the Arctic Oscillation, which operates across the whole Northern Hemisphere.
The US and Canada are in for a real battle this autumn.
Think of it as a battle of the heavyweights. In the north corner of the ring, it’s the Arctic Oscillation. Its punishing blows can knock you out cold. In the west corner lurks the El Niño. Don’t let the name, which means “little boy”, fool you. He can come roaring out with a cold punch to the South and hot and heavy in the North.
The El Niño is weak but may pack a warm punch later.
Oh, and just to make the battle even more interesting – in the east corner is the hot Atlantic. This battler has been the past champion, dominating the ring, baking the US with scorching hot temperatures. The champion is not going to give up easily.
On Saturday, September 22, the opening bell rang and autumn starts. The battle to see which forces shape this fall’s weather will begin. In short, the hot dry summer is finally dragging to a close and a stormier fall is about to begin.
Let’s pretend that there is a ringside announcer. He is sizing up Round 1 – the opening week of autumn.
The Champion, the hot Atlantic still controls the ring. The US is still warm and dry, but it looks like he is getting tired. Some cooler temperatures are entering the South.
The cold Arctic Oscillation is entering the ring. Those winds that trap polar air north are weakening and some cooler air is surging into the Great Lakes and the Midwest. Already we are seeing snowflakes over the Great Lakes. The AO won’t do much this round, but he is shaping up to be a real contender. This winter will be colder than last winter.
Originally posted by FissionSurplus
The freezing air going over the warm lakes causes the heavy snow, right?